1. Field of the Invention
The present invention relates to a game system for moving an object on a screen according to an operating direction of a direction indicating section of an input device; and a program for configuring such a game system.
2. Description of the Related Art
In a video game machine for executing a so called board game such as chess, movement of a player's piece on a board face is generally controlled according to an operation relevant to the direction indicating section provided on an input device (controller). At the direction indicating section, an operating section is provided in four directions, i.e., vertical and horizontal directions form a predetermined location as a center, alternatively, in eight directions in which diagonal line directions thereof are added. As a typical example of such a direction indicating section, there is one provided an operating member so called a cross shaped key. Alternatively, there is another example in which a push button type operating member is located vertically and horizontally to function as one direction indicating section.
In the meantime, there is a specific direction on a game board face displayed on a game screen, alternatively, a specific direction at a direction indicating section of an input device. A predetermined correlation is defined between the direction specific to the direction indicating section and the direction specific to the game board face. In general, the correlation is defined so that the direction specific to the game board face displayed on a screen and the operating direction of the direction indicating section coincide with each other. For example, where the game board face is displayed so that, on the screen, the player's side is located at the lower side, and the counterpart's side is located at the upper side, the direction indicating section is operated in an upper direction from the viewpoint of the player, whereby the player's owned piece advances at the upper side of the screen, namely, toward the counterpart's side.
In a board game such as chess executed on a conventional video game machine, its board face is configured comparatively simply, and an image of such a game board face is limited to a still picture on which the game board face is scanned from a predetermined viewpoint (for example, a right above viewpoint) However, with improvement of the three-dimensional image processing capability of the game machine, in a game of such type as well, it has become general that a game board face and objects such as pieces located on the game board are depicted by a using three-dimensional computer graphics. In the case where a game board face is depicted as a three-dimensional image, it is possible to change a viewpoint, and then, present images of the game board face in a variety of directions.
However, in the case where an image of the game board face is changed according to a change of viewpoint, a correlation between the direction specific to the screen and the direction specific to the game board face are also changed together with such a change. For example, where the upper direction of the screen coincides with the piece advancing direction before change of the viewpoint, there occurs a change, for example, the game board face rotates on the screen together with the change of viewpoint, whereby the right oblique upper direction of the screen coincides with the piece advancing direction. Even in the case where such a change occurs, when a correlation between the direction specific to the game board face and the direction specific to the direction indicating section provided on the input device is constantly maintained, a correlation between the piece moving direction on the game board face and the operating direction of the direction indicating section becomes constant irrespective of the orientation in the screen of the game board face. For example, in the case where an operation in the upper direction of the direction indicating section is associated with the piece advancing direction, the player operates the direction indicating section in the upper direction when the piece is advanced irrespective of whether the piece advancing direction on the game board face is in the upper direction of the screen or in the right oblique upper direction.
However, in a home use video game machine, the player often operates an input device while holding it in a predetermined direction. Specifically, the player of ten holds the input device in a posture in which the vertical and horizontal directions on the screen and that of the direction indicating section substantially coincide with each other. Therefore, when the direction specific to the screen and the direction specific to the game face dose not coincide, there is a possibility that the player may get confused relevant to the operation of the direction indicating section. For example, in the case where the right oblique upper direction of the screen coincides with the piece advancing direction, there is a possibility that the player cannot discriminate immediately to operate the direction indicating section in the upper direction or right direction from the player's view in order to advance the piece.